Conductive Hydrogels as a Medium for Shapeable Catheter Ablation Electrodes
Listed in
This article is not in any list yet, why not save it to one of your lists.Abstract
BACKGROUND
Radiofrequency catheter ablation (RFCA) uses rigid metallic electrodes whose fixed geometry limits tissue contact, lesion continuity, and safe energy delivery near vulnerable structures. We evaluated a moldable, tissue-conforming conductive hydrogel as an RFCA electrode ex vivo .
METHODS
Poly(ether urethane diacrylamide) hydrogels with saline-tuned conductivity were molded into plugs, disks, and bars and affixed to an irrigated 8-Fr catheter. Ablations were performed on excised porcine tissue in circulated saline at 37 °C under fixed contact force and irrigation. Lesion geometry, intramural temperatures, and steam pops were compared with bare-metal (BM) electrodes and size-matched metallic analogs; an atrioesophageal stack model assessed collateral injury. Lesions were delineated using triphenyltetrazolium chloride staining.
RESULTS
Hydrogel bars produced wide, ellipsoidal lesions (width 10.51 ± 1.40 versus 8.71 ± 1.65 mm for BM; P =0.031; aspect ratio 1.72); size-matched metal bars produced none. Hydrogel disks produced lesions statistically indistinguishable from BM in depth (4.54 ± 0.90 versus 4.84 ± 0.55 mm) and width (9.47 ± 0.89 versus 11.41 ± 2.39 mm), whereas metal disks produced significantly shallower lesions (2.30 ± 1.70 mm; P =0.015 versus BM). In the atrioesophageal model, hydrogel plugs achieved transmural atrial lesions with a reduced esophageal lumen temperature (56.33 ± 3.80 versus 61.30 ± 5.14 °C; P =0.046), total lesion depth (4.03 ± 1.25 versus 7.58 ± 0.78 mm; P <0.001), and esophageal lesion width (3.05 ± 2.35 versus 8.70 ± 2.69 mm; P <0.001) compared with BM. Hydrogel electrodes reduced steam-pop risk (relative risk 0.34; 95% CI 0.13–0.88). Plug characterization confirmed saline-dependent conductivity and attenuated energy delivery, with lower subsurface peak temperatures and shallower lesions than BM.
CONCLUSIONS
Moldable, conductivity-tunable hydrogels shape RF lesions and may improve ablation safety, supporting evaluation for contiguous or linear lesion sets and ablation near sensitive structures.
CLINICAL PERSPECTIVE
What Is Known
• Radiofrequency ablation catheters use rigid metallic electrodes, so contiguous lesion sets require sequences of closely spaced burns, and irregular tissue surfaces or thin atrial tissue near the esophagus limit uniform, safe energy delivery.
• Conductive hydrogels can be molded into arbitrary shapes and tuned in electrical conductivity, but their use as a radiofrequency ablation electrode medium has not been characterized.
What the Study Adds
-
In an ex vivo porcine model, a molded hydrogel bar electrode produced wide, ellipsoidal lesions where a size-matched metal bar produced none, and a hydrogel disk produced lesions comparable to a standard bare-metal electrode where the size-matched metal disk was significantly shallower.
-
Hydrogel electrodes attenuated energy delivery, achieving transmural atrial lesions with lower esophageal lumen temperatures, smaller esophageal lesions, and lower steam-pop risk than a bare-metal electrode.
-
These properties support conductive hydrogel electrodes for linear lesion sets and ablation near sensitive structures, pending in vivo validation.
